Method for predicting water cut increasing rate of water-drive oil field

Abstract

The invention relates to a method for predicting the water cut increasing rate of a water-drive oil field. The method includes the following steps that cylindrical rock samples are taken from a natural rock core of the oil field, a rock core displacement experiment is performed, and a series of parameters such as water saturation Sw, oil phase relative permeability Kro and water phase relative permeability Krw are obtained; irreducible water saturation Swi and residual oil saturation Sor are obtained, and the oil and water viscosity ratio mur is obtained through measurement; the relations between the oil and water relative permeability ratio and the water saturation, the reflected relational expression between the water content and the recovery percentage, and the relational expression between the water cut increasing rate and the recovery percentage are obtained with a power method. According to the method, oil and water relative permeability materials are utilized, a power type mathematical processing method is adopted, the water content and the water cut increasing rate of the oil field are described, the development effect and the development degree of the oil field are analyzed and evaluated, development measures are planned according to the method, the yield of the oil field is reasonably planned and deployed, and more effective guidance can be provided for development of the oil field.

Description

technical field [0001] The invention relates to the technical field of oil development reservoir engineering, and more specifically, the invention relates to a method for predicting the change of water cut rise rate in a water drive oilfield. Background technique [0002] Oil-water relative permeability is an important data that reflects the characteristics of underground oil-water two-phase seepage, and is an important basic data for reservoir engineering research. It can be used to predict reservoir water cut, water cut change, water cut rise rate change, and recovery factors. . With the deepening of the development process, more and more medium-high permeability sandstone reservoirs will enter the ultra-high water-cut development stage (comprehensive water cut greater than 90%), and the development rules of reservoirs in this stage are different from those in the medium-high water-cut development stage. At present, the methods for characterizing relative permeability cur...

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Problems solved by technology

However, there will be a large error between the calculation result and the actual data near the two endpoints of irreducible water saturation and residual oil saturation. During the calculation process, this error will be retained and will be substituted into the subsequent reservoir analysis. Detrimental effects on reservoir dynamic analysis and planning scheme preparation

In particular, the above-mentioned relative permeability curve characterization method has the following disadvantages: ① The change of oilfield development indicators in the low water-cut stage is inconsistent with the water flooding characteristic curve, and the oil-water relative permeability ratio with e -b·Sw It is not a linear relationship, and the water cut in mine production tends to rise faster; ②The relative permeability curve at a higher water injection multiple has a piecewise nonlinear feature. At this time, the influence of the oil-water relative permeability ratio on the actual production water cut If the relative permeability curve is relatively small, the characterization accuracy of the relative permeability curve at this stage is not high, and the oilfield development index changes conform to the characteristics of the water drive curve; Permeability ratio with e -b·Sw The linear relationship is no longer completely linear as usual, and the linear relationship is only suitable for the middle section of the relative permeability curve, but cannot represent the complete relative permeability curve; Permeability experiment) thinks that the efficiency of water flooding is generally lower than 60%, while the closed core analysis of the mine believes that the efficiency of water flooding can exceed 70%, and the conventional relative permeability curve cannot accurately describe the seepage characteristics under high water injection multiples

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